As an avid letterboxd user, 5 stars.

5 - excellent. No issues. 4-4.5 - great and has minor issues that can generally be over looked. 3-3.5 - average. Not much that really stands out to me as amazing. 1-2.5 - bad. Some aspects may be good but the bad outweighs them. The closer to one, the worse it is. 0.5 - awful. Nothing redeeming about it.